RFID systems, RFID tags, and RFID readers are well known, and they are utilized in many different applications such as inventory control, shipping, asset tracking, vehicle toll booths, and point-of-purchase. An RFID reader interrogates RFID tags, which provide tag data that can be collected, interpreted, displayed, or otherwise processed by the RFID reader or other elements of the RFID system. In practice, UHF RFID readers have a read zone or volume of space that can sometimes be difficult to control due to multipath effects or reflections of the RF signal that extend the range of an RFID reader over what is expected in an otherwise free space environment.
At times it is necessary to isolate an RFID tag physically in order to distinguish it from a larger population of tags. Examples of where this situation occurs are in retail point of sale, baggage handling, or any application where it is necessary to reliably identify an RFID-tagged item from a large group of tagged items using UHF RFID readers. Spatial isolation of an RFID tag may be difficult if the interrogation range of the RFID reader is not easily controlled or adjusted to a lower power setting. Problems that occur with conventional RFID readers include reading RFID tags that are not in the desired field of view or that are located at adjacent reader locations. This can lead to errors in customer purchases or errors in verification that an item is in a specific physical location (e.g., baggage on a specific cart).
In an effort to reduce the problems outlined above, some RFID readers may be capable of changing from a far-field reader to a near-field or contact reader. In practice, the ability to quickly and easily change the read zone of an RFID reader is essential for applications where the user will be challenged to isolate items within a large group and perform a read, write, or kill function on the RFID tag associated with the isolated item. However, conventional dual-mode RFID readers typically require complicated, lengthy, or cumbersome manipulation to switch between far-field and near-field modes. For example, it may be necessary to access and manipulate a number of different user interface features such as graphical menus, buttons, and confirmation screens before the RFID reader can function in the near-field mode.